Yamaha Lower Unit Assembly – 6G9-45300-03-EK

OEM Yamaha Gearcase Replacement for Reliable Propulsion

The Yamaha Lower Unit Assembly – 6G9-45300-03-EK is a genuine factory-built gearcase designed to restore smooth, efficient power transfer on your Yamaha outboard. As a complete OEM assembly, it arrives with key components—including the gear housing, driveshaft, propeller shaft, bearings, seals, and shift shaft—pre-installed and factory-tested. This ensures a precise fit, easy installation, and Yamaha-grade reliability without the guesswork of rebuilding an old unit.

Note: This part supersedes earlier assembly 6E0-45300-03-8D and has now been replaced by Yamaha’s updated part number 6G9-45300-06-EK. Always confirm fitment for your exact model before ordering.

Key Features

• Complete OEM Assembly: Includes housing, shafts, gears, and seals—ready to install out of the box.
• Precision Fitment: Factory-built to match Yamaha specifications, eliminating alignment issues or tolerance mismatches.
• Durable Construction: Built with marine-grade materials designed to resist corrosion and wear in saltwater or freshwater use.
• Plug-and-Play Replacement: No need to transfer old internal parts—drop-in installation saves time and effort.

Compatibility

Part Number: 6G9-45300-03-EK (superseded from 6E0-45300-03-8D, later replaced by 6G9-45300-06-EK)
Designed for select Yamaha 2-stroke outboards in the mid-horsepower range. Please consult your Yamaha parts diagram or technician to confirm compatibility with your specific model and year.

Ideal Use Cases

• Major Gear Damage: Replace failed or seized lower units to restore propulsion.
• Saltwater Corrosion: Swap in a new sealed unit when corrosion compromises housings or seals.
• Engine Restoration: Perfect for refurbishing older Yamaha outboards to factory performance.

Why Choose a Genuine Yamaha Lower Unit?

The lower unit is one of the most critical and high-stress parts of your outboard. Choosing a genuine Yamaha assembly ensures exact tolerances, proper sealing, and long-term reliability. Unlike aftermarket gearcases, this unit arrives fully assembled and Yamaha-tested, saving you from installation errors and extending the life of your motor.

Frequently Asked Questions

Does the unit come pre-filled with gear oil?
No, the unit is shipped dry. It must be filled with Yamaha-approved lower unit gear oil before operation.

Is this a brand-new OEM part?
Yes, this is a brand-new, factory-assembled Yamaha gearcase—not rebuilt or remanufactured.

Do I need a mechanic to install this?
While experienced owners may handle installation, Yamaha recommends professional installation for correct alignment, sealing, and torque specifications.

Is there a break-in period?
Yes. Yamaha recommends a brief break-in period, avoiding sustained full-throttle use for the first 10 hours.

• Supersessions
  6G9-45300-00-EK, 6G9-45300-01-EK, 6G9-45300-02-EK, 6G9-45300-04-EK, 6G9-45300-05-EK, 6G9-45300-06-EK, 6G9-45300-06-EK